GROMYKO LEAVES POLITBURO, RETIRES FROM SOVIET PRESIDENCY DOBRYNIN ALSO STEPS DOWN AS AMBASSADOR TO U.S.

President Andrei A. Gromyko was retired from the ruling Politburo and his post as president Friday at his own request, a top Soviet official said.

Gromyko, 79, was named president in July 1985 after serving a succession of Soviet leaders as foreign minister for nearly 30 years. He was replaced as foreign minister by Eduard V. Shevardnadze.The move could clear the way for Mikhail S. Gorbachev to seek election to a new, more powerful presidency.

Vadim A. Medvedev, a spokesman for the Communist Party Central Committee, said Mikhail S. Solomentsev, 75, also had been retired as a full member of the Politburo and head of the Party Control Commission.

In what appeared to be the biggest single power shift in the Kremlin since Gorbachev took power, Anatoly F. Dobrynin, the longtime Soviet ambassador to Washington, was sent into retirement from his post as party foreign affairs secretary.

He had been regarded as a key Gorbachev adviser but had never been elevated to the ruling Politburo.

Medvedev, a secretary of the Communist Party Central Committee, said he had been elevated to full Politburo status.

KGB chief Viktor M. Chebrikov was named a secretary of the Central Committee to go along with his Politburo status, and two new alternate members of the Politburo were named, Medvedev said.

Alexandra Biryukova, the highest-ranking woman in the Soviet hierarchy, gained an alternate Politburo spot as did Anatoly Lukyanov.

The moves came on the first day of a hastily called meeting of the Communist Party's policy-making Central Committee to discuss reorganization of the party structure in line with Gorbachev's reforms.

Medvedev did not immediately specify the reason for the retirement of Gromyko.

Gorbachev lauded "the merits and achievements" of Gromyko and wished him the best, indicating he was leaving in good standing.

Tass said earlier that the Central Committee session would consider "proposals on reorganization of the party apparatus in the light of the decisions of the 19th Communist Party conference."

At that congress in June, the Soviet leader outlined a series of political reforms. His blueprint calls for the creation of a full-time, standing legislature and a more powerful presidency.

During the June conference, one delegate harshly criticized Gromyko and Solomentsev by linking them to former President Leonid I. Brezhnev. His period of leadership is now regarded as a period of stagnation and corruption.

There has been speculation that Gorbachev's backers want to remove 60 to 70 "dead souls" from the Central Committee. They are party leaders elected to the committee shortly after Gorbachev took power in March 1985 but who since then have lost party or government jobs that entitled them to committee membership.